序列化未实现序列化的外部板条箱枚举的 vec

Question

我将外部 crate 与不实现序列化的枚举一起使用，我想在包含此枚举的 Vec 的结构中使用它，并有可能取消/序列化此结构。基于我创建的以下代码的serde文档

use serde::{Serialize, Deserialize};
#[derive(Debug, PartialEq, Eq)]
enum ExternalCrateColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
#[serde(remote = "ExternalCrateColor")]
enum LocalColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
struct Hue {
#[serde(with = "LocalColor")]
color: ExternalCrateColor
}
fn main() {
let tones = Hue { color: ExternalCrateColor::Blue };
let serialized = serde_json::to_string(&tones).unwrap();
println!("serialized = {}", serialized);
let deserialized: Hue = serde_json::from_str(&serialized).unwrap();
if deserialized.color == ExternalCrateColor::Blue {
println!("Blue tones");
}
}

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但我想要的是让 Hue 结构包含 ExternalCrateColor 的 Vec：

struct Hue {
#[serde(with = "LocalColor")]
colors: Vec<ExternalCrateColor>
}

并且它不起作用，因为在这种情况下，反序列化需要单个外部CrateColor。如何让它工作？

Answer 1

我不认为您可以使用serde的远程类型功能来完成这项工作，但是您可以通过首先定义转换来完成：

fn to_local(color: &ExternalCrateColor) -> LocalColor {
match color {
ExternalCrateColor::Red => LocalColor::Red,
ExternalCrateColor::Green => LocalColor::Green,
ExternalCrateColor::Blue => LocalColor::Blue,
}
}
fn to_external(color: &LocalColor) -> ExternalCrateColor {
match color {
LocalColor::Red => ExternalCrateColor::Red,
LocalColor::Green => ExternalCrateColor::Green,
LocalColor::Blue => ExternalCrateColor::Blue,
}
}

使用这些转换，您可以像这样实现它：

fn color_vec_ser<S: Serializer>(
vec: &Vec<ExternalCrateColor>,
serializer: S
) -> Result<S::Ok, S::Error> {
// First convert the vector into a Vec<LocalColor>.
let vec2: Vec<LocalColor> = vec.iter().map(to_local).collect();
// Instead of serializing Vec<ExternalCrateColor>, we serialize Vec<LocalColor>.
vec2.serialize(serializer)
}
fn color_vec_deser<'de, D: Deserializer<'de>>(
deserializer: D
) -> Result<Vec<ExternalCrateColor>, D::Error> {
// Deserialize as if it was a Vec<LocalColor>.
let vec: Vec<LocalColor> = Deserialize::deserialize(deserializer)?;
// Convert it into an Vec<ExternalCrateColor>
Ok(vec.iter().map(to_external).collect())
}
#[derive(Debug, Serialize, Deserialize)]
struct Hue {
#[serde(serialize_with = "color_vec_ser")]
#[serde(deserialize_with = "color_vec_deser")]
colors: Vec<ExternalCrateColor>
}

Answer 2

我需要检查serde的代码库，但我能够通过黑客使其工作。

use serde::{Serialize, Deserialize};
#[derive(Debug, PartialEq, Eq,)]
enum ExternalCrateColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
#[serde(remote = "ExternalCrateColor")]
enum LocalColor {
Red,
Green,
Blue
}
#[derive(Debug, Serialize, Deserialize)]
struct Adapter {
#[serde(with = "LocalColor")]
color: ExternalCrateColor
}
#[derive(Debug, Serialize, Deserialize)]
struct Hue {
colors: Vec<Adapter>
}
fn main() {
let adapters = vec![Adapter {  color: ExternalCrateColor::Blue }, Adapter {color: ExternalCrateColor::Green}];
let hue = Hue {colors: adapters};
//     let tones = Hue { color: ExternalCrateColor::Blue };
//     let serialized = serde_json::to_string(&tones).unwrap();
//     println!("serialized = {}", serialized);
//     let deserialized: Hue = serde_json::from_str(&serialized).unwrap();
//     if deserialized.color == ExternalCrateColor::Blue {
//       println!("Blue tones");
//     }
}

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